Merge pull request ros2#17 from alsora/asoragna/minor-clean

minor cleanup of comments and spin_some timeout

rclcpp/include/rclcpp/executors/events_executor.hpp

@@ -168,11 +168,12 @@ class EventsExecutor : public rclcpp::Executor
   void
   execute_event(const ExecutorEvent & event);
 
-  // Event queue members
+  // Event queue
   std::queue<ExecutorEvent> event_queue_;
+  // Mutex to protect insertion and extraction of events in the queue
   std::mutex event_queue_mutex_;
+  // Variable used to notify when an event is added to the queue
   std::condition_variable event_queue_cv_;
-
   // Timers manager
   std::shared_ptr<TimersManager> timers_manager_;
 };

rclcpp/include/rclcpp/executors/events_executor_entities_collector.hpp

@@ -103,11 +103,9 @@ class EventsExecutorEntitiesCollector final : public rclcpp::Waitable
 
   /// List of weak nodes registered in the events executor
   std::list<rclcpp::node_interfaces::NodeBaseInterface::WeakPtr> weak_nodes_;
-
   /// Executor using this entities collector object
   EventsExecutor * associated_executor_ = nullptr;
-
-  // Instance of the timers manager used by the associated executor
+  /// Instance of the timers manager used by the associated executor
   TimersManager::SharedPtr timers_manager_;
 };
 

rclcpp/src/rclcpp/executors/events_executor.cpp

@@ -101,6 +101,11 @@ EventsExecutor::spin_some(std::chrono::nanoseconds max_duration)
   }
   RCLCPP_SCOPE_EXIT(this->spinning.store(false););
 
+  // In this context a 0 input max_duration means no duration limit
+  if (std::chrono::nanoseconds(0) == max_duration) {
+    max_duration = timers_manager_->MAX_TIME;
+  }
+
   // This function will wait until the first of the following events occur:
   // - The input max_duration is elapsed
   // - A timer triggers
@@ -230,6 +235,7 @@ void
 EventsExecutor::add_node(
   rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr, bool notify)
 {
+  // This field is unused because we don't have to wake up the executor when a node is added.
   (void) notify;
 
   // Add node to entities collector
@@ -246,6 +252,7 @@ void
 EventsExecutor::remove_node(
   rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr, bool notify)
 {
+  // This field is unused because we don't have to wake up the executor when a node is removed.
   (void)notify;
 
   // Remove node from entities collector